At present, old corrugated paper board, or card board, is the most valuable fraction to be recovered from solid waste material which also includes plastic and paper sheets and strips, bottles, cans, metal straps, wood, tires and the like, as well as sand, rocks, dust, dirt and other debris.
It is estimated that in the United States alone, up to 250 million tons of solid wastes are generated each year.
Interest is growing in the beneficial handling of these vast quantities of material owing to the fact that various fractions are often susceptible of being reused or recycled, with a resultant conservation of energy, natural resources and reduction in the amount of refuse to be buried or wastefully burned.
The technology of large scale solid waste classification and sorting is advancing; and the patent literature is not without representative systems, exemplary being the disclosures in U.S. Pat. No. 2,151,894, for Apparatus For Sorting Household Rubbish, granted Mar. 28, 1939, to Cambessedes and U.S. Pat. No. 2,307,059, for Apparatus For Separating Garbage, granted Jan. 5, 1943, to Moore.
Despite the foregoing disclosures and the existence of various solid waste sorting installations in numerous locations, both here and abroad, there remains considerable room for improvement, owing in part to the fact that the latter years have witnessed the proliferation of both light gauge plastic sheeting, used for a myriad of purposes, and lengthy strips of paper, such as the long strips carrying computer readouts. These lighter materials have heretofore been especially difficult to separate from corrugated paper board.